The work presented in this paper forms part of a wider research programme being undertaken on water and ionic movement within the cover region of structural concrete and the evaluation of the properties that, ultimately, determine durability. The developments in monitoring techniques employed in the testing programme are detailed, with particular emphasis on the application of electrical methods. Data are presented that highlight the testing methods and the interpretation of the results. Examples are given of other uses of the data to provide additional information on the electrical and physical properties of concrete, and on its moisture state. In particular, it is shown that it is possible to determine such factors as rates and depths of water penetration, degree of saturation and porosity of the concrete cover, and the resistivity of the concrete at the level of the reinforcement.